The following is based on information from Van Buren design documents and is not canon.
Discover lost Hoover Dam war and Sub-level 1 history and relaying information to FOA was going to be a quest in Van Buren, the canceled Fallout 3 by Black Isle Studios.
Once the player has found Hoover Dam Sub-Level 1C, he must contend with the nasty centaurs and floaters in the area. Once they are eliminated, the player may safely dig around the computer archives (computer still works thanks to Hoover's generators) and discover a few bits about Hoover's history. The better Science skill the PC has, the more info he can extrapolate. Relay this information back to the Followers of the Apocalypse and they will smile. In fact, they may even give a few books to the PC.
Character type completion breakdown
Combat, Diplomacy, Stealth Boy - Must... kill... nasties... Then must figure out how to use a computer (easy).
Science Boy - If he can get rid of the critters, then the computers are no problem.